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94a8921e9d
There was no actual execution of the SQL of a pushed derived table, which caused "r_rows" to be always displayed as 0 and "r_total_time_ms" to show inaccurate numbers. This commit makes a derived table SQL to be executed by the storage engine, so the server is able to calculate the number of rows returned and measure the execution time more accurately
113 lines
3.1 KiB
C++
113 lines
3.1 KiB
C++
/*
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Copyright (c) 2018, 2019 MariaDB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02111-1301 USA */
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#include "mariadb.h"
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#include "sql_priv.h"
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#include "sql_select.h"
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#include "derived_handler.h"
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/**
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The methods of the Pushdown_derived class.
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The objects of this class are used for pushdown of the derived tables
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into engines. The main method of the class is Pushdown_derived::execute()
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that initiates execution of the query specifying a derived by a foreign
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engine, receives the rows of the result set and put them in a temporary
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table on the server side.
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The method uses only the functions of the derived_handle interface to do
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this. The constructor of the class gets this interface as a parameter.
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Currently a derived tables pushed into an engine is always materialized.
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It could be changed if the cases when the tables is used as driving table.
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*/
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Pushdown_derived::Pushdown_derived(TABLE_LIST *tbl, derived_handler *h)
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: derived(tbl), handler(h)
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{
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}
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int Pushdown_derived::execute()
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{
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int err;
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THD *thd= handler->thd;
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TABLE *table= handler->table;
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TMP_TABLE_PARAM *tmp_table_param= handler->tmp_table_param;
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DBUG_ENTER("Pushdown_derived::execute");
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if ((err= handler->init_scan()))
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goto error;
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while (!(err= handler->next_row()))
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{
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if (unlikely(thd->check_killed()))
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{
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handler->end_scan();
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DBUG_RETURN(-1);
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}
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if ((err= table->file->ha_write_tmp_row(table->record[0])))
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{
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bool is_duplicate;
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if (likely(!table->file->is_fatal_error(err, HA_CHECK_DUP)))
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continue; // Distinct elimination
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if (create_internal_tmp_table_from_heap(thd, table,
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tmp_table_param->start_recinfo,
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&tmp_table_param->recinfo,
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err, 1, &is_duplicate))
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DBUG_RETURN(1);
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if (is_duplicate)
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continue;
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}
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}
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if (err != 0 && err != HA_ERR_END_OF_FILE)
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goto error;
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if ((err= handler->end_scan()))
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goto error_2;
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DBUG_RETURN(0);
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error:
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handler->end_scan();
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error_2:
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handler->print_error(err, MYF(0));
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DBUG_RETURN(-1); // Error not sent to client
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}
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void derived_handler::print_error(int error, myf errflag)
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{
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my_error(ER_GET_ERRNO, MYF(0), error, hton_name(ht)->str);
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}
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void derived_handler::set_derived(TABLE_LIST *tbl)
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{
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derived= tbl;
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table= tbl->table;
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unit= tbl->derived;
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select= unit->first_select();
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tmp_table_param= ((select_unit *)(unit->result))->get_tmp_table_param();
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}
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